ISO 16701:2003 pdf download

ISO 16701:2003 pdf download.Corrosion of metals and alloys —Corrosion in artificial atmosphere -Accelerated corrosion test involvingexposure under controlled conditions of humidity cycling and intermittent spraying of a salt solution.
4.2 Spraying device
The spraying device for salt solution installed in the climate chamber shall be capable of producing a finely distributed uniform vertical downward flow of mist or small droplets falling on the test objects at a linear flow rate of 15 mm h±5 mm h-1.
If a graduated glass cylinder with a collecting area of 80 cm2 is used to check whether this flow rate is within the specified range, the collection rate of salt solution shall be 120 ml h-1 ± 40 ml h-1.
The device for salt spraying is preferably made of a number of nozzles mounted in series on a rail or tube. A spray pattern in the form of a fan, partly overlapping, is then obtained. The spraying device shall be made of, or lined with, materials resistant to corrosion by the salt solution and which do not influence the corrosivity of the sprayed salt solution. The use of molybdenum-alloyed stainless steel or plastic is recommended. Figure B.2 shows a suitable design of spraying device.
Salt solution that has already been sprayed shall not be re-used.
4.3 System for forced drying
The climate chamber shall be equipped with a system for forced air flow drying, as after spraying/wet stand-by all test objects should be dried from excessive macro wetness and climate control shall be made possible to regain within a reasonable time.
Forced drying is preferably arranged by supercooling and reheating an internal circulating flow. Alternatively, drying may be arranged by letting a forced flow of pre-heated ambient air ventilate the chamber. For a climate chamber of the volume 1 m3 to 2 m3 an air flow rate of 50 ls to 100 Is-1 is recommended. The forced air flow shall not be pre-heated to such temperature levels that the maximum chamber temperature of 35 °C is exceeded.
NOTE Pre-heating of the forced air flow to a temperature of 40 °C has been found suitable from practical experience.
5 Test objects
5.1 The number and type of test objects, their shape and their dimensions shall be selected according to the specification for the material or product being tested. When not specified accordingly, these details shall be mutually agreed between the interested parties.
5.2 For each series of test objects, data records shall be kept and include the following information.
a) Specification of material to be tested; e.g., for surface-treated materials: type of base material, its pretreatment, type of coating, method of application and dry film thickness.
b) If the test specimen is subjected to intentional damage in the coating, the shape and the location of the damage should be described, as well as how the damage was achieved. The orientation of the damage during testing should also be specified.
If the test objects are cut from a larger coated article, cutting shall be carried out in such a way that the coating is not damaged in the area adjacent to the cut. Unless otherwise specified, the cut edges shall be adequately protected by coating them with a suitable material, stable under the conditions of the test, such as paint, wax or adhesive tape.
c) Information on cleaning procedure to be used prior to testing.
d) Information on reference material or materials with which the test specimen is to be compared.
e) How the test object is to be examined and which properties are to be assessed, see e.g. Clause 7.
6 Procedure
6.1 Arrangement of the test objects
The test objects shall be placed in the cabinet on stands with their test surface facing upwards. The angle atwhich the surface of the test specimens is exposed in the cabinet is important. For flat test objects the angle atwhich the test surface is inclined shall preferably be 20° ±5° to the vertical. In the case of irregular surfaces,e.g. entire components, this angle shall be adhered to as closely as possible.